<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <script src="https://cdn.jsdelivr.net/npm/vue@2.7.14/dist/vue.js"></script>
</head>
<body>
  <div id="app">
    <p>请选择你要购买的书籍</p>
    <ul>
        <li v-for="item in arr" :key="item.name">{{item.name}} <button @click="item.count++">买书</button></li>
    </ul>
    <table border="1" width="500" cellspacing="0">
      <tr>
        <th>序号</th>
        <th>书名</th>
        <th>单价</th>
        <th>数量</th>
        <th>合计</th>
      </tr>
      <tr v-for="(item,index) in arr" :key="item.name">
        <th>{{index+1}}</th>
        <th>{{item.name}}</th>
        <th>{{item.price}}</th>
        <th>{{item.count}}</th>
        <th>{{item.price*item.count}}</th>
      </tr>
    </table>
    <p>总价格为:{{zong}} </p>
  </div>
  <script>
    const app = new Vue({
      el: '#app',
      data: {
        arr: [
          {
            name: "水浒传",
            price: 107,
            count: 0,
          },
          {
            name: "西游记",
            price: 192,
            count: 0,
          },
          {
            name: "三国演义",
            price: 219,
            count: 0,
          },
          {
            name: "红楼梦",
            price: 178,
            count: 0,
          },
        ]
      },
    //   methods:{
    //     zong(){
            
    //     }
    //   },
      computed:{
       zong:{
        get(){
            return this.arr.reduce((sum,item)=>sum+item.price*item.count,0)
        }
       }
      }
    })
  </script>
</body>
</html>